Click for next page ( 56

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement

Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 55
APPENDIX C INTEGRATION IN MANUFACTURING SYSTEMS ABROAD No country in the world yet claims to have a complete set of workable procedures for integrating the subsystems of a total manufacturing operation. The approaches currently being applied differ according to the traditions, resources, economic systems, and aims of the various countries. Nevertheless there is considerable cross-fertilization (e.g. [1,2,3~) and general optimism. JAPAN In Japan a concurrent scheme of two strategies has been operating since the mid-1960s. The first of these strategy-components has been a succession of government-sponsored and organized projects for the theoretical and experimental study of long-term fundamentals (Direct Numerical Control, followed by the "Methodology of Unmanned Manufac- turing," and now the "Flexible Manufacturing System Complex with Lasers. Each of these projects has helped to develop a national terminology; a consensus among management, government, labor, financiers, and technicians on long-term aims and limitations; a framework for shorter-se'= company tactics; a general appreciation of the need for standardization and the limitations it imposes; and, finally, a sound foundation for training the CAD/CAM engineers of the future. Parallel with their active and enthusiastic participation in these long-term projects, the Japanese companies have developed mainly pragmatic methods for integrating machine tools and transport equipment into flexible manufacturing systems (FIRS). Machining information--generally in International Standards Organization (ISO) or RS tape format--is transmitted to standard CNC units in what is little more than an accelerated BTR (behind-the-tape reader) mode, and is stored there (mostly in bubble memories). The "tape" information is generated off-line, by computer-aided manual numerical control (NC) programming procedures, but these are very rarely linked organically to CAD or even to computer-aided process planning. Two integrative features, on the other hand, are very advanced indeed: one of these is the on-line scheduling of the systems (which in fact pulls the 55

OCR for page 55
56 whole act together at a very high level); the other is the advanced monitoring and failure-detection apparatus that makes "unmanned machining" pass ible in the second and third shifts . Current research work at the leading Japanese univers ities is aimed at the development of geometric modeling and process planning systems (GEOMAP, TIPS) which hopefully will allow the numerous extant FMS plants to take a s tep toward CAD/CAM integration. At the same time the factories are' exploiting the previous efforts invested in standardization by offering a broad spectrum of manufacturing "modules," "cells," and "islands," which can--at a relatively low systems level--be fairly easily linked and then integrated by high-level scheduling. At this time a proposal is in an advanced stage toward acceptance for the establishment of a national program on "Manufacturing Softwar Engineering." This will use the "Flexible Manufacturing System Complex with Laser" hardware as a test bed for the entire life-cycle of complete CIM sys tems . EUROPE e In Europe, the USSR and Germany have a long-standing tradition (dancing back to the late 1920s ~ of concern with the scientific determination of cutting technologies. This has led in the Soviet Union and the two postwar German states to the concentration of much effort on computer-aided parts classification, process planning (determination of cutting condition, machine and tool selection, optimal trajectory determination), the establishment of machinability data banks, etc. In due course the highly developed suites of programs developed for these purposes came to be regarded as the principal mode for designing manufacturing systems for integrating CAD and CAM and for providing data to scheduling. Internal part represen- tations were based on the process classification schemes. In recent years, however, academic research has been oriented toward increasing the weight of geometrical modeling as the integrative factor. In the USSR there is currently a very powerful concentration of resources on the rapid implementation of EMS in a large number of plants (e.g., 16 agricultural machinery plants are now simultaneously installing such systems). The key word is standardization: the plants are all using the same computers, the same control units, and the same modular software system (MEMO), with many standardized subsystems, standard tooling, pallets, fixtures, etc. [4~. In these systems the link to CAD is rather tenuous, but the process planning systems (and their links to scheduling and manufacture) are very powerful. A rather similar approach is being adapted in Czechoslovakia. France and Hungary have traditions in mathematical abstraction and analysis. In both countries computer-based systems have been developed and are being industrially tested for the analysis and synthesis of large, highly integrated systems. Taking as their points of departure the ideas originally proposed by Hori and Ross in the

OCR for page 55
57 United States and later embodied in the ICAM Definition program, researchers have sought to integrate these with the facilities of Petri-nets, relational data bases, simulation techniques, interactive graphics, etc., to offer the designer a broad palette of interrelated design tools. The initial industrial experiences have pleased users in both countries. The United Kingdom and France have long been pioneers of numerical geometry and later of geometric modeling. (Bezier first integrated the design and manufacture of automobile bodies; Braid invented set-theoretic solid modeling.) In both these countries an intimate integration of design and manufacture has been,achieved in a few selected areas (mainly automotive and aerospace). Similarly, integrated CAD/CAM systems are now appearing--e."., for mold and die manufacture. None of these, however, has links to scheduling and management. Finally, mention should be made of the work being conducted in a number of countries (e.g., Norway, UK, Japan, USSR) to develop multilayer, multiuser data base management systems that, it is hoped, will cover the whole area and facilitate integration. It is also hoped that these will later operate in a distributed mode through local-area networks. (The latter--and particularly their standardization--are of course themselves powerful factors for integration.) Joint German-Norwegian CAD/CAM Integration Program Through agreements between the West German and Norwegian govern- ments, a joint German/Norwegian R&D program is under way called Advanced Production System (APS). It is aimed at joint development of an integrated CAD/CAM system. The prime members are Fraunhofer Institute for Production Planning and Design Engineering, Technical University of Berlin; the Laboratory for Machine Tools and Manufac- turing Engineering, Technical University of Aachen, West Germany; the Foundation for Scientific and Industrial Research, Norwegian Institute of Technology, Trondheim, Norway; and the Central Institute for Industrial Research, Oslo, Norway. In addition, some 13 industrial companies in the two countries are participating in the program. These include seven system suppliers (four from Germany, three from Norway) and six system users (three from Germany, three from Norway). The program began in early 1981, and a short-term phase will run through 1985, with a long-term phase running through 1990. These phases are intended to produce a first-generation integrated system (for sale or use by the participating companies), based on integration of existing software modules, by 1985, and a second-generation integrated system, developed from scratch, by about 1990.

OCR for page 55
58 CONCLUSION It is apparent (and appreciated by all the countries concerned) that none of the methods they have separately or jointly developed is as yet suitable for the fool-proof design and implementation of the "factory of the future." However, all of the methods have some thin" to offer and have allowed spectacular progress to be made. It is widely appreciated that only the synthesis of the extant approaches, the deepening of our theoretical understanding, and, above all, the acquisition and sharing of much more practical experience can lead to a usable "science" of integration. References t1] Advances in CAD/CAM (T.M.R. Ellis, I.I. Semenkov, Eds.), North-Holland, Amsterdam, 1983. Papers~on "Design and implementation of integrated CAD/CAM systems" from France, GDR, Norway, USSR, Czechoslovakia, FRG, Japan, Finland. [2] Integration of CAD/CAM (D. Kochan Ed.), North-Holland, Amsterdam, 1984. Papers from Hungary, FRG, Bulgaria, Japan, GDR, Czechoslovakia, Holland, France. t3] PTK 83. Die Zukunft der Fabrik. Carl Hauser, Munchen, 1983. Papers from USA, FRG, Japan, Norway, Hungary. ~ -, [4] EVM v proyektirovanie i proizvodstve. (G.V. Orlovski Ed.) Mashinos troenie , Leningrad, 1983 .